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Let constraint compiles

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This commit is contained in:
Richard Feldman 2019-08-28 21:08:11 -04:00
parent 49cd2ede8a
commit 7308ef24c0
4 changed files with 40 additions and 54 deletions
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50
src/solve.rs
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@ -15,10 +15,11 @@
use subs::{Subs, Variable, Descriptor, Content, FlatType};
use collections::ImMap;
use canonicalize::Symbol;
use types::Constraint::{self, *};
use types::Type::{self, *};
type Env = ImMap<String, Variable>;
type Env = ImMap<Symbol, Variable>;
pub fn solve(env: &Env, subs: &mut Subs, constraint: Constraint) {
println!("\nSolving:\n\n\t{:?}\n\n", constraint);
@ -37,48 +38,31 @@ pub fn solve(env: &Env, subs: &mut Subs, constraint: Constraint) {
},
Let(box_let_constraint) => {
let let_con = *box_let_constraint;
let no_rigid_vars = let_con.rigid_vars.is_empty();
match let_con.ret_constraint {
True if no_rigid_vars => {
True => {
// If the return expression is guaranteed to solve,
// and there are no rigid vars to worry about,
// solve the assignments themselves and move on.
solve(env, subs, let_con.assignments_constraint)
},
body_con => {
if no_rigid_vars && let_con.flex_vars.is_empty() {
// Solve the assignments' constraints first.
solve(env, subs, let_con.assignments_constraint);
ret_con => {
// Solve the assignments' constraints first.
solve(env, subs, let_con.assignments_constraint);
// Add a variable for each assignment to the env.
let new_env = env.clone();
// Add a variable for each assignment to the env.
let mut new_env = env.clone();
for (name, loc_type) in let_con.assignment_types {
let var = type_to_variable(subs, loc_type.value);
for (name, loc_type) in let_con.assignment_types {
let var = type_to_variable(subs, loc_type.value);
new_env.insert(name, var);
}
// Now solve the body, using the new env which includes
// the assignments' name-to-variable mappings.
solve(&new_env, subs, let_con.ret_constraint);
// TODO do an occurs check for each of the assignments!
} else {
let vars = let_con.rigid_vars;
vars.extend(let_con.flex_vars);
// Add a variable for each assignment to the env.
let new_env = env.clone();
for (name, loc_type) in let_con.assignment_types {
let var = type_to_variable(subs, loc_type.value);
new_env.insert(name, var);
}
new_env.insert(name, var);
}
// Now solve the body, using the new env which includes
// the assignments' name-to-variable mappings.
solve(&new_env, subs, ret_con);
// TODO do an occurs check for each of the assignments!
}
}
},